1. Field of the Invention
The present invention relates generally to the concrete construction and paving fields, and more specifically to a device for use with a mobile slip form concrete barrier construction machine. The present invention secures to such a machine and serves to guide preassembled steel reinforcement grids or screens into place as the barrier is formed, placing the reinforcement accurately within the concrete barrier as it is formed.
2. Description of the Related Art
Hundreds, if not thousands, of miles of concrete traffic barrier or retaining walls (i. e., xe2x80x9cJersey wallsxe2x80x9d) are placed or constructed annually during road and highway construction, building and parking lot construction, pavement resurfacing, etc. During temporary repaving or construction projects, most such barriers are prefabricated in predetermined lengths and temporarily placed in location as desired, using a crane or other suitable means. However, in many cases such barriers are intended for permanent placement, e. g., as dividers between opposed lanes on highways, traffic separators in areas where no shoulders exist along the roadway, as in crowded urban areas, etc.
Where such barriers are intended to be permanently installed, it is oftentimes more economical to construct the barriers in place, rather than prefabricating them in sections, transporting them to the site, and placing them as desired. As a result, machines have been developed which essentially extrude such concrete barriers as a continuous line, for use where a relatively long length of permanent barrier is desired.
The use of steel bars or other steel reinforcement in concrete structures is well known, and is known to increase the strength of concrete structures considerably. Accordingly, virtually all concrete traffic barriers or retaining walls make use of such steel reinforcement within the concrete structure. Such concrete barriers use at least a few reinforcement bars placed linearly therein, with additional steel reinforcement in the manner of one or more mats, grids, or screens being even more desirable.
While the use of reinforcing steel screens is desirable for the superior strength provided to the finished barrier, in the past their use has resulted in a relatively costly finished product. Either the contractor must buy (or make) prewelded reinforcement mats, or pour an additional footer and imbed the steel reinforcement structure in the footer and then form the concrete barrier around the reinforcement steel. Each of the above methods adds considerably to the cost of the completed job. In the case of welded steel mats, the welding reduces the strength of the steel at each welded joint, thus requiring the contractor to purchase higher strength (and more expensive) steel in order to meet the specified strength requirements of the contract. Hand tied mats are superior in this respect, but in the past have been difficult to incorporate in a concrete barrier structure without resorting to the additional step of pouring a separate concrete footer and imbedding the steel reinforcement in the footer, before pouring the barrier itself.
Accordingly, a need arises for a device for guiding placement of steel reinforcing mesh into a mobile continuous barrier forming machine, during the forming process. The present insertion guide is installed on the forming machine and positioned between the slip form mold walls. The present invention enables two preassembled reinforcing mats to be tied together at their upper edges, with the central separator of the guide serving to separate the two mats and spread them apart at their upper edges, positioning them accurately within the concrete as it is poured continually into the slip form.
A discussion of the related art of which the present inventor is aware, and its differences and distinctions from the present invention, is provided below.
U.S. Pat. No. 2,175,240 issued on Oct. 10, 1939 to Oscar F. Arthur, titled xe2x80x9cApparatus For Placing Reinforcement In Concretexe2x80x9d describes a generally horizontally oriented machine for forcing a single ply of reinforcing mesh downwardly into a fresh concrete surface, as in a concrete roadway, floor slab, etc. The Arthur machine cannot operate in a generally vertical plane, as it is not configured to operate with a slip form barrier mold. Moreover, the Arthur machine can only handle one ply of mesh at a time, rather than the two plies which the present invention is capable of handling.
U.S. Pat. No. 2,596,206 issued on May 13, 1952 to Fred D. Carnes, titled xe2x80x9cDowel Bar Installing Device,xe2x80x9d describes a machine for placing dowel and tie bars into a horizontal poured concrete structure (paving, slab, footing, etc.). The device comprises a series of hooked fingers each supporting a dowel rod or the like, with the rods sliding from the hooks when they contact the fresh concrete. Each hook has an upper part which engages the rods to force them downwardly into the concrete, with the fingers clearing the rods when the fingers are lifted from the concrete. The Carnes machine cannot insert two plies of steel reinforcing mesh or screen into opposite sides of a concrete structure, nor can it install such reinforcing steel in a generally vertical structure or into a structure as it is being formed, as provided by the present guide.
U.S. Pat. No. 3,443,495 issued on May 13, 1969 to Carl J. Heltzel, titled xe2x80x9cConcrete Reinforcing Steel Handling And Placing Device,xe2x80x9d describes a machine for picking up reinforcement bars and the like and carrying them over freshly poured concrete, and placing them atop the concrete. The Heltzel machine does not actually place or locate the reinforcement bars within the concrete; this must be done by a separate machine. The Heltzel machine cannot be used with generally vertical concrete structures, as it merely places the reinforcement material atop a freshly poured horizontal slab. Also, the Heltzel machine cannot provide more than a single ply of reinforcement steel for the concrete, as the ply of steel placed is defined by the upper layer of fresh concrete upon which the steel is placed by the Heltzel device.
U.S. Pat. No. 3,678,816 issued on Jul. 25, 1972 to Michael I. Hudis, titled xe2x80x9cApparatus For Installing Reinforcing In Plastic Concrete,xe2x80x9d describes a machine for depressing reinforcing rods or bars into freshly poured concrete, comprising a wheel having a series of paddles thereon for pushing the steel reinforcement into the concrete. The Hudis device thus performs essentially the same function as the devices of the Arthur ""240 and Carnes ""206 U.S. Patents discussed further above, and cannot guide or feed multiple plies of preassembled steel reinforcing mesh or screen into a generally vertical concrete structure as it is being continually and linearly formed, as provided by the present insertion guide invention.
U.S. Pat. No. 4,084,928 issued on Apr. 18, 1978 to Adolph R. Petersik, titled xe2x80x9cSlip Form Having Reinforcement Accommodating Means,xe2x80x9d describes a slip form mold having a hinged door or panel on the forward end thereof. The door includes slots and passages therein, for allowing continuous lengths of reinforcing rod or bar to pass through the closed door and into the mold, where it is encapsulated within the concrete. The slots of the door of the Petersik device extend laterally, with the ends being closed off when the door is closed. Thus, the Petersik device does not provide clearance thereinto for multiple plies of continuous preformed screens or meshes having a length and substantial width, as provided by the present insertion guide. Moreover, the Petersik device cannot be lifted for obstruction clearance (curbs, etc.) while in operation, as can the present reinforcement insertion guide.
U.S. Pat. No. 4,168,135 issued on Sep. 18, 1979 to Henry S. Johansson et al., titled xe2x80x9cCasting Machine With Reinforcement Inserting Device,xe2x80x9d describes a device for inserting transverse tie bars into freshly poured concrete, in a slip form mold for forming concrete barriers. The device is external to the mold, rather than being installed within the mold as in the case of the present invention. The Johansson et al. machine deposits a series of separate, single reinforcement bars transversely atop the fresh concrete and forces them downwardly into the concrete. The Johansson et al. device does not serve as a guide for accurately positioning continuous lengths of reinforcement grid or screen material longitudinally into the length of the barrier as it is poured, as provided by the present reinforcement insertion guide.
U.S. Pat. No. 4,433,936 issued on Feb. 28, 1984 to Andreas Moser, titled xe2x80x9cDevice For Driving And Positioning Dowels Into Concrete Slabs,xe2x80x9d describes a machine which performs a similar function to that of the Arthur ""240, Carnes ""206, and Heltzel ""495 U.S. Patents discussed further above. As in those other devices, the Moser machine inserts relatively short lengths of lateral reinforcing rod from above, vertically downwardly into a freshly poured slab of concrete as in a roadway, foundation, etc. The Moser machine, as with the others noted above, is incapable of guiding continuous lengths of reinforcement screens disposed generally on edge into a slip form mold for forming a generally vertical concrete barrier wall, as provided by the present insertion guide invention.
U.S. Pat. No. 4,493,584 issued on Jan. 15, 1985 to Ronald M. Guntert, titled xe2x80x9cApparatus And Process For Dowel Insertions,xe2x80x9d describes an automatic feeder machine which singly picks up dowels from a supply of such dowels, and distributes and inserts them into a freshly poured concrete slab from above. The Guntert machine thus bears a closer resemblance to the machines of the Carnes ""206, Heltzel ""495, and Moser ""936 U.S. Patents, than to the present invention. As in the other devices discussed to this point, the Guntert machine cannot be used as a guide for the insertion of continuous lengths of reinforcing steel mesh or screens into the leading end of a concrete barrier slip form machine, as provided by the present insertion guide invention.
U.S. Pat. No. 5,993,108 issued on Nov. 30, 1999 to Gerald L. Buhman, titled xe2x80x9cDowell (sic) Rod Inserter,xe2x80x9d describes a pneumatic device for securing to the side of a slip form concrete casting machine, such as a curb or pavement forming machine. The Buhman device extends laterally from the slip form, and inserts dowels singly and laterally into the plastic concrete through a slot in the side of the slip form, before the concrete has cured. As in the case of the other prior art devices known to the present inventor, the Buhman device is incapable of guiding one or more elongate prefabricated steel reinforcement grids or screens longitudinally into the leading end of a slip form, which function is provided by the present insertion guide invention.
Finally, Japanese Patent Publication No. 10-220,009 published on Aug. 18, 1998 to Oriental Construction Company, Ltd. et al., describes (according to the drawings and English abstract) the formation of a pocket in a concrete structure, into which a jack is placed. The jack applies compressive force to a reinforcing rod installed in the concrete structure, to apply stress to the concrete for greater strength. The apparatus and method of the ""009 Japanese Patent Publication is not closely related to the present invention, as the concrete structure to which the reinforcing steel is applied is not stressed in the present invention, and the steel reinforcement is applied to plastic, uncured concrete in the present invention, as opposed to the application of the Japanese apparatus and method to cured concrete.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
The present invention comprises an adjustable reinforcement insertion guide for use with mobile slip form machines for forming continuous lengths of concrete barrier walls (i. e., xe2x80x9cJersey wallsxe2x80x9d). The present invention provides a means for accurately guiding the placement of prefabricated reinforcement steel screens or grids into the leading end of such a mobile slip form machine, thereby providing superior strength to the resulting cured concrete barrier.
The present insertion guide installs within the leading end of a slip form mold, and includes inlet guide panels for accurately guiding and placing the steel reinforcement structures into the slip form mold as the concrete is being introduced therein. The present guide is adjustable, with the height being vertically adjustable in order to provide clearance and accurate spacing for curbs, open cut joints, etc. as required. The device also includes adjustable rearward guide panels, which may be adjusted laterally to provide more accurate guidance and placement for the steel reinforcement as it passes through the guide. The present guide is the only device of which the present inventor is aware, which is capable of accurately placing two prefabricated steel reinforcement screens within a slip form mold simultaneously, without requiring prior preparation as by setting up the reinforcement in previously poured footings, etc.
Accordingly, it is a principal object of the invention to provide an improved reinforcement insertion guide for use with a slip form concrete barrier mold, for accurately guiding steel reinforcement into the slip form.
It is another object of the invention to provide an improved reinforcement insertion guide which is vertically adjustable to provide clearance for curbs and the like as required.
It is a further object of the invention to provide an improved reinforcement insertion guide which vertical adjustment is accomplished by hydraulic means.
An additional object of the invention is to provide an improved insertion guide including further adjustment means for guiding the steel reinforcement laterally through the guide.
Still another object of the invention is to provide an improved reinforcement insertion guide which provides for the insertion of two laterally spaced steel reinforcement screens simultaneously to each side of the center of the mold.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become apparent upon review of the following specification and drawings.